William Jay Youmans

“ The inability to speak, after loss or mutilation of the tongue, is sometimes due, not so much to the lack of that organ, as to the state of the sufferer's mind. Like those patients with impaired locomotive powers who, believing they cannot walk, seem to lose the power of will necessary to enable them to try to walk, the person with an imperfect tongue, laboring under the impression that talking is impossible, fails to make the necessary effort, and perhaps would never regain the faculty of speech unless startled into some involuntary exclamation that convinces him of his mistake. ”

“ One of the surest ways in which an eminent man can cause his influence to live after him is in training up younger men to lives of usefulness. This Dr. Hosack was constantly doing. “I can scarcely recollect the time,” says his son, “when he was without some such project.” At one time it was the son of a New York carpenter, who, unfortunately, fell a victim to his devotion to yellow-fever patients in the epidemic of 1798. ”

“ With this hasty sketch of the heat-producing and heat-regulating functions of the animal economy, we pass to a brief consideration of some of the more important ill-effects resulting from the action of excessive heat on the conditions of health and on the body itself.
High temperature is a powerful aid to decomposition. Dead organic matter, under its influence, speedily decays, giving rise to foul and poisonous products which, escaping into the atmosphere, find their way, sooner or later, into the system. ”

“ Among those whose debtor I am, stands first and foremost the clear head and warm heart of this Dutch officer, whom I am proud to call my friend. He is an ornament to his profession, and a more accomplished officer it has never been my good fortune to meet in any service. Jansen has served many years in the East Indies. ”

“ Although the luminous force acts only upon the nerve of the eye to stir up a sensation, yet we know how infinitely complex and varied is the world of color that results. There is evidence that the dark thermal and chemical radiations are of equal variability and complexity, yet there can be no doubt that all these multitudinous effects are due to a single mode of action. The difference between the thermal and the chemical rays is simply the difference between the red and the green ”

“ In the early part of the nineteenth century no citizen of New York was held in higher honour than was De Witt Clinton. Closely associated with Clinton in the leadership of the civic life of the day, but holding rigidly aloof from politics,was Dr. Hosack. “It was not infrequently remarked by our citizens,” said his pupil and associate, John W. Francis, “that Clinton, Hosack, and Hobart were the tripod on which our city stood.” Dr. Hosack was one of the founders of the New York Historical Society and its president from 1820 to 1828. ”

“ Jansen was the chief promoter of a revival of Arctic exploration in Holland, being ably, and, indeed, enthusiastically, seconded by his young friend, Lieutenant Koolemans Beynen. The veteran sailor always felt the warmest sympathy for the aspirations of his youthful brother officers; and his encouragement of the patriotic ardour of young Beynen led to the formation of an Arctic Committee at the Hague, and to an appeal to the public for funds. ”

“ But, when we are told that the ray enters the eye at the rate of 185,000 miles per second, and—as each inch contains 57,000 waves—that when we are looking at a violet object there are 699,000,000,000,000 beats upon the retina each second, the statement baffles all imagination: we may accept, but cannot understand it. In the attempt to penetrate the nature of light we are lost in the mysteries of the infinite. ”

“ Botany was not the only branch of science in which he became interested while abroad. To quote from a sketch of his life by a friend:
“He attended in the winter of 1793–'94 the first course of lectures on mineralogy that was delivered in London by Schmeisser, a pupil of Werner. With this additional knowledge of mineralogy, which Dr. Hosack had begun to study at Edinburgh, he continued to augment the cabinet of minerals which he had commenced in Scotland. ”

“ Commodore Jansen had become an honorary corresponding member of The Royal Geographic Society in 1865, and always took a deep interest in the proceedings and the society’s welfare. The society had never had a correspondent who was so ready and anxious to assist them by every means in his power. When the question of an Arctic expedition was under discussion, Jansen gave up much time to an examination of the Dutch Archives, with a view to a study of the ice in the Spitzbergen Seas, as reported by the Dutch whalers during the last three centuries. ”

“ We patch together different shreds of our mental experience of large things, and construct a symbolic idea which represents our planet, but we never grasp the reality in the immensity of its proportions.
Light is a force, and science holds that it is made up of impulses. ”

“ It is not light that makes the picture, but dark radiations that are associated with it, and that have the peculiar effect of producing changes in certain chemical compounds.
Although photography, in its wonderful development as an art, belongs to the past generation, yet the knowledge of the chemical effects ascribed to light is as old as chemical science. ”

“ Of course the effect of such abrupt transitions from perfect illumination to total darkness, if it were the plan of Nature, would be most inconvenient and painful, if not destructive to the eyes. We are protected from this by the phenomena of double shadows, and the gradual passage from darkness to light, although each luminous ray moves undeviatingly in its straight line. ”

“ Somehow, in their mysterious nature, the luminous rays from all sources, distant and remote, effect a change in the nerve-structure of the eye by which impressions are transmitted to the brain. Into that mode of action we cannot now enter, but will confine our attention at present to the property of light by which luminous images are produced. For it is, after all, the images of things we have to deal with. We know the external world in its distances, forms, and colors, because its visible objects are all duplicated in the eye. ”

“ Not that the body can bear unlimited exposure to great heat, any more than it can endure continuous exertion, but that it is capable of maintaining itself under even excessive heat, if the exposure is not too prolonged. ”

“ Although obesity may be ranked among the diseases arising from original imperfection in the functions of some of the organs, it is also, without doubt, most intimately connected with our habits of life. The inconveniences arising from it are, therefore, to be removed by correcting those habits, especially such as relate to diet and regimen. Drugs without number have been tried, both for the removal of corpulence itself, and for the many troubles to which it gives rise; but they have almost uniformly failed when diet and exercise have been neglected. ”

“ If, by exposure to cold, for example, heat is lost more rapidly from the surface than it is supplied within, its warmth must decrease, and there needs but a few degrees of fall to induce disease; on the other hand, if, by exposure to external heat, loss from the body is impeded, its temperature rises, and disease again results.
In hot climates, or during the hot season in temperate latitudes, we are in contact with an atmosphere which frequently attains a temperature nearly or quite equal to that of the body ”

“ In children and in females, especially in early age, the principal seat of the fatty deposit is in the cellular tissue, immediately under the skin. During adolescence, the fat has a tendency to disappear from this situation; but, about middle age, frequently becomes again deposited, not only in the subcutaneous tissues, but also in the neighborhood of certain internal viscera. The quality of the fat also varies, both with the age and with the part in which it is deposited. It is firmer and higher colored in old persons than in young ones ”

“ But, when thus exposed, the extensive evaporating surfaces of the lungs and skin are called into more active play; and, if the air is of average dryness, heat is rapidly thrown off by perspiration, the loss being so nicely adjusted that a uniform temperature of 99° Fahr. is continuously maintained. This heat-regulating function of the organism is one of the marvels of physiology. In spite of the vicissitudes of climate and season, it ever holds the temperature at a uniform degree, and, even under the stress of high artificial heat, is able to keep the balance comparatively unchanged. ”

“ In all these instances heat appears to act not so much upon the body itself as upon the various external agencies influencing health. It is to bad conditions what fire is to powder. If the match is withheld, the powder is harmless; but, as the two are liable to come together, we secure safety by removing the magazine. So the presence of filth in water, in soil, and above-ground, may be innocuous by itself, but let the action of heat touch it off into decomposition, and we at once get the effects in the shape of disease. ”

“ It has been thought that the nitrogenous foods are consumed chiefly in the formation of the tissues, while the non-nitrogenous are devoted mainly to the function of respiration, going principally to the maintenance of the animal temperature. Whatever basis in fact this view may have, it is pretty well established that the substances belonging to the latter class of foods are especially favorable to the production of fat, when taken into the system. This fat may exist ready formed in the food, as it is furnished abundantly by both the animal and vegetable kingdoms ”

“ The sense of taste, which, to according many physiologists, is properly limited to the perception of the acid, bitter, sweet, or saline properties of food, does not appear to suffer; but the power to recognize and enjoy flavors, which is commonly associated with taste, but which in reality belongs to the nose, is sometimes lost along with the sense of smell. Access of air to the middle ear through the Eustachian tubes is an essential to the sense of hearing, and this, too, is greatly interfered with oftentimes by the fatty thickening of the mucous membrane of the nose and throat. ”

“ THE healthy human body has a temperature which varies but little either way from 99° Fahr. The heat required to maintain this temperature is derived from the oxidation within the body of the elements of the food. In other words, our bodies are furnaces; the food we take is the fuel which supplies the furnace, and the air we breathe is the draught that keeps the combustion going. The amount of heat thus evolved is, in health, always in excess of that needed to maintain the required temperature. ”

“ This fact is illustrated by numerous instances both among the lower animals and among men. At Strasbourg, the geese are fattened by shutting them up in darkened coops within a heated room, and stuffing them constantly with food. The high temperature lessens the escape of heat, and thus favors the process. Here all the conditions for insuring obesity are resorted to—viz., external heat, obscurity, inactivity, and the cramming of the animals with fattening food. A still greater refinement for pandering to the appetite is resorted to by the Italians who relish the fat of the ortolan. ”

“ The pupils fail to respond to the action of light, and may be somewhat contracted, the breathing becomes hurried and difficult, and the action of the heart is irregular and tumultuous. Convulsions may come on early, or be postponed until late in the disease, or they may be absent altogether. Numerous minor and less constant phenomena have been recorded by different observers; but, when a person is suddenly attacked during exposure to great heat, the symptoms already enumerated will enable any one of ordinary intelligence to recognize the true character of the disease. ”

“ Sunstroke, or the disease hitherto passing under that name, though known since early times, is even yet not well understood. Up to within a few years, it was believed by patient and physician alike that, to produce it, the body, and especially the head, must be exposed to the direct rays of the sun. There is now abundance of proof to the contrary. ”

“ If we construct a conical surface touching the body all round, and having its vertex at the luminous point, it is evident that all the space within this surface on the farther side of the opaque body is completely screened from the rays. The cone thus constructed is called the shadow-cone, and its intersection with any surface behind the opaque body defines the shadow cast upon that surface. In the case which we have been supposing—that of a luminous point—the shadow-cone and the shadow itself will be sharply defined. ”

“ WITH that proneness to go wrong, which we notice in most things human, and which crops out in science as well as elsewhere, the art of making pictures by the chemical action of radiant forces has got a false name. ”

“ The more constant, as given by the best authorities, are great heat and dryness of skin, a varying degree of pain in the head, attended oftentimes with giddiness, congestion of the eyes, full, rapid pulse, which grows feeble and irregular as the disease advances, obstinate constipation, irritability of bladder, and great oppression or sense of weight about the region of the heart, with not unfrequently muscular weakness and a disinclination for exertion. If these symptoms continue, the patient soon passes into a state of profound insensibility. ”

“ Heat thus aids the pollution of both air and water, keeps alive and active the germs of disease in the excreta of the sick, and in both ways favors the spread of contagion.
Its direct action upon the person becomes most apparent when some of the functions are going wrong. When the body is healthy, and proper precautions are taken in its management, there is little to fear from exposure to heat. ”

“ Light cannot turn corners like sound. This is explained by the excessive shortness of the luminous as compared with sonorous waves. Sound-waves are so large that they flow around objects in the air, and consequently cast but feeble shadows, although Deschanel (from whose admirable work on "Natural Philosophy" our cuts are borrowed) states that Collodon, in his experiments on the transmission of sound through the water of the Lake of Geneva, established the presence of a very sharply-defined sound-shadow in the water behind the end of a projecting wall. ”

“ Nature has been shown to conform all kinds of dynâmical effects to rhythmical pulsing, or wave-like action and the impulses of light are held to be of the same kind. There are, at any rate, measurable effects which are unequal in the different colored lights, and the scale has been determined. In an inch of violet light it is shown that there are no less than 57,000 waves, a statement in which there is nothing extraordinary or impossible, as Nobert, the German optician, is in the habit of ruling his microscopical test-glasses at rates all the way from 100,000 to 200,000 per inch. ”